IIT JEE , AIEEE Forum - Physics , Mechanics

tibu

A car can be stopped over a distance s when its momentum is P.What will be the stopping distance when the momentum is 2P?

ans:4s.

Please explain how.

george

ruhi

hi

let us take the initial velocity of car be 'u'

thus p=mu

final velocity = v = 0 nd since car stops after a certain distance hence it is retarding

we know that v^2=u^2+2as

thus 0=u^2-2as

therefore s=u^2/2a - (1)

now when momentum is 2p, obviously the velocity becomes 2u so substituting (2u) in place of u then s'=4u^2/2a=4s.

hey it was rather a simple question

puneet

this is correct ruhi. bravo

assumption here is that the acceleration (i.e. deceleration) is constant in both cases (a safe assumption

)